Afterburner exhaust nozzle variable area



Jan. 27, 1959 R. G. GLENN AETERBURNER EXHAUST NozzLE VARIABLE AREA Filed Feb. 13, 1956 3 Sheets-Sheet 1 5 Sheets-Sheet 2 INVENTOR. j 42 EA/A/ Men- Jan. 27, 1959 R. G. GLENN AETERBURNER EXHAUST NozzLE VARIABLE AREA Filed Feb. 15, 195s Jan. 27, 1959 R. G. GLENN AFTERBURNER EXHAUST NozzLE VARIABLE AREA Filed Feb. 1s, 195e 3 Sheets-Sheet 3 INVENTOR. @ser 615// Y.

United States Patent AFTERBURNER'EXHAUST NOZZLE y vVARIABLE AREA l 'Robert-G. Glenn, Merriam, Kans., -assignor, by mesne lassignments, to the United States. of America as repre- 'sente'd by thefSecretary of the Navy Application February 13, 19s6,-seria1N0.s6 s,z79 1 Claim. (c1. ao-ssis) actuator which was capable of producing even higher ipressures. In-the instant device, advantage is taken of the -pressures vdeveloped by the engine to aid in lcontrolling the area of the exhaust nozzle.

Applicants invention consists of a plurality of leaves positioned toform a circular opening atfthe exhaust end of a jet engine. These leaves arepivotally attached to a .unison ring which is moved along the longitudinal axis of .the jet.. engine. To every otherleaf'aroller, ywhich bears against the engine fairing, is secured. Movement ofthe unison ring causes the leaves to move in and out due to :the camming action of the failing and-roller-to varythe yeffective area of the exhaust nozzle. Y Y

1t-is .an object of this device toprovide anieans for rapidly controlling the area of the exhaust nozzle for a jet engine.

lt is a further object of this invention to use the forces developed by the exhaust pressure to put a forward and aft thrust on the actuator to balance the gas forces and thus reduce the required actuator force.

It is a further object of this invention to provide fairing on the leaves which will permit a minimum of turbulence at the rear of the engine or base drag resulting in a higher speed for a given thrust.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. l is a segment of the tail section of a jet engine with the open position of the exhaust nozzle shown in full lines and the closed position sho-wn in dotted-dash lines.

Fig. 2 is a showing of the driven leaf in section taken along the line 2-2 of Fig. l.

Fig. 3 is a showing of the floating leaf with the leaf fairing in section taken along the line 3-3 of Fig. l.

Fig. 4 is a section showing the location of the leaves taken along the line 4-4 of Fig. 3.

Fig. 5 is a view looking along the line 5-5 of Fig. 2.

Fig. 6 is a transverse section, looking rearward, of a fully open jet engine exhaust nozzle taken substantially adjacent the forward end of the unison ring.

In the drawings there is shown a segment of the tail section of a jet engine. This segment discloses means for varying the exhaust nozzle area.

ln Figure 1 there is disclosed a segment of a double wall circular casing the outer wall of which constitutes the exhaust nozzle fairing 1 of a jet engine. The fairing 1 VAtapers in an aftward direction from a point 1g of maxivfairing 1.

1is obtained permitting lighter structure. ing-thev exhaustl nozzle Afairing'as a camming surface, 'the ice mumdiameter to ajpoint "1b ofrminimum diameter and surrounds the exhaust nozzle area.

Locatedv on the inner sideof thefairing f1' are a plnrality of driven'leaves 2l and floating'leaves'. *The'ifull Vline position indicates theopenpositionor-maximum ex haust nozzle area and the dotted lines indicate'the closed position or minimumy exhaust nozzle area. 4The-leaves are moved between thel open and closed positionsibyaunison ring4,` as shown in FigurejZ The unisonring'fis moved 'fore and Yaft by two lor more 'push-rods-5 which move through'a lloatingseal ring 26 inpartitionwall 27 of the The push rods Iare pivotally vconnectedv to blocks'6 ofthe unison ring 'by the `pins `7 andthe unison ring rides'on springs t; bearing' againsttheinner-wall `1C of the'casing and formin'g's'eal's. A plurality 'ofhinge plates 9 are secured tothe unisonring completely around ythe exhaustnozzle'. In the open position the leaves are held inposition by resilient ring member 28 when the engine is not operating.

A plurality of leaves are pivotally connected to 'the'uni- 'son ring :4*byfpiano type hinges "10. AEvery alternate leaf isa drivenA leaf 2 which are somewhat triangular in crosssection. Near the apex of the triangular shape, aroller 'Il is mounted which is held against 'the fairing 12 of the casing b y the gaspressures `emanating from the jet `engine 'through fthe'exhaust nozzle andbearing on the basek sec- 'tion 13 of the leaf.

K By mounting the-rollerjneai the centerrof the leafa minimum-cantilever action on the leaf Also, byv utilizy exhaustA nozzle fairing serves aY purpose other than merely a shield. Thus, we ightV issaved. The rearward .sectionv of the drivenleaf has a curvedfaii-ing 1'4'xe`d'to' it. fWhen the leaf is in an extended position the fairing -r14 serves to `streamline the rear or base of the engine and reduce Aturbulencebehind`v it; thus, it minimizes'the resulting drag which issnormally c'alledbase drag. `The driven leaf is strengtl'lened'byv ribs 23 mounted between the `base A*13 and the fairing 14.

Between each driven leaf, a floating leaf 3 is mounted. The base portion 15 of the floating leaf has angled end sections 16 which bear against the base section 13 of the driven leaf. The iloating leaf is mounted on the inner side of the driven leaf and is held against the driven leaf by the gas pressures issuing from the exhaust nozzle. A strengthening rib 17, U-shaped in ,cross-section, extends along the full length of the longitudinal axis of the floating leaf. At approximately the midpoint of the rib 17 is secured a support 18 with upstanding ears 19 having apertures 20. A leaf fairing 21 having pins 22 is pivotally supported in the apertures 20. The iloating leaf fairing bears on the inner side 24 of the driven leaf fairing and is held against the driven leaf fairing by resilient retaining tabs 25 secured to the ribs 23. The leaf fairing serves to permit a minimum base drag resulting in higher air speeds for a given thrust.

Pivotally mounting fairing 21 on the driven leaf 3 assures a seal between leaf fairings or elements 14 and 21 and elements 13 and 15.-i. e. there are two seals on each lateral edge of a leaf-while permitting free sliding action between the leafs for movement of the device back and forth from open to close po-sitions. Otherwise, a clearance, as between elements 14 on leaf 2 and element 21 on leaf 3. is required where element 21 is rigidly mounted and is spaced relative with element 15 on leaf 3. ln this case only one of the mentioned seals would be obtained on each side of a leaf which would depend on the spacing of element 2,1 from element 15 on leaf 3 with relation to the spacing of element 14 from element 13 on leaf 2. Where the spacing o-n leaf 3 is smaller than on leaf 2 only the seal between elements 13 and 15 would be Obtained and vice versa when the spacing is larger.

The'operatiou of the invention is best explained in connection with Figure 2. The movement of the driven leaf 2 from the solid line position of Figure 2 to the dotted line position is initiated by the push rods 5 controlled byv the operator. As the push rod is'moved, it actuates the unison ring 4 through the connection 7.v Since all the leaves 2 and 3 are pivotally connected to the unison-'ring 4 by the hinges 10, the leaves are all moved at the same 4 l The roller 11 of theA Vdriven leaf bears against the exhaust nozzle fairing which time and in the same direction.

serves as a cam surface and drives the end of leaf 2 toward the center of the exhaust nozzle area. The ram forces from the engine coming through the exhaust tend and a curved fairing element on the outer surface of each leaf thatfollows the contour of'said outer wall extending angled end sections 16'of the floating leaf toward Vthey e center of the exhaust nozzle area. The ram forces of the engine exhaust force the floating leaf against the driven leaf.

` When the leaves are in an extended position the fairing on the driven leaves and the oating leaves cooperate with` the fairing on the exhaust nozzle section to present a sym` metrical system. Thus, only a minimum base drag is permitted resulting in higher speeds at a given thrust.

Obviously many modifications and variations of the present invention are possible in the light of the abovev It is therefore to be understood thatrwithin Y the scope of the appended claim the invention may be teachings.

practiced otherwise than as specifically described.

Whatis claimed is: Y Y Apparatus for controlling the area of the exhaust nozzle tending rearward from said nozzle, said casing including an annular cylindrical inner wall and an annular outer wall, a portion of said outer wall extending rearward beyond said inner wall and having a tapered inner surface,

an axially reciprocable ,annular unison ring positioned between said Walls, a plurality of circumferentially spaced outer ldriving leaf elements disposed longitudinally between said walls in axial alignment with said unison ring, a plurality of circumferentially spaced inner driven leaf elements interposed between and inwardly of said outerV leaf elements, the lateral edge portions of each of said outer leaves overlying the adjacent edges on said inner leaves, said inner and outer leaf elements cooperating'to form a substantially annular member, hinge means secured to and in axial alignment with Vsaid unison ring and said leaves for permitting inward tilting of said leaves, a roller mounted at substantially the center of each of said driving .leaves and bearing against the inner surface of ysaid outer wall so that longitudinal, rearwardmovement of said rollers on said 'tapered surface forces Vsaid leaves to tilt toward the center of the nozzle to reduce its area,

from its rearward end to substantiallyl they center of said leaf, the lateral edge portion on said fairing elements on K said driving leaves overlying'those on theV driven leaves,

of a jet engine comprising a cylindrical tube defining a` combustion chamber terminating in an exhaustnozzle, a

double wall casing closed at one end secured to andex- Y urged outwardly to hold said lateral vedges said fairing on Ysaid driven leaves being pivoted attheir forward ends tothe Ydriven leaves Vand being'resiliently gagement.

References Cited inthe file of this Ypatent UNITED STATES PATENTS 2,778,190 Bush Jan. 22, 1957 2,779,157 Palmer l Jan.29,19s7

Y FOREIGN PATENTS f 1,018,650 France Oct. 15, 1952 1,071,851 France Mar. 1o, 1954 Great Britain July 14, 19754 in sealing enf 

